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1.  A screening based approach to circumvent tumor microenvironment-driven intrinsic resistance to BCR-ABL+ inhibitors in Ph+ acute lymphoblastic leukemia 
Journal of biomolecular screening  2013;19(1):158-167.
Signaling by the BCR-ABL fusion kinase drives Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) and chronic myelogenous leukemia (CML). Despite their clinical activity in many patients with CML, the BCR-ABL kinase inhibitors (BCR-ABL-KIs) imatinib, dasatinib, and nilotinib provide only transient leukemia reduction in patients in Ph+ ALL. While host-derived growth factors present in the leukemia microenvironment have been invoked to explain this drug resistance, their relative contribution remains uncertain. Using genetically-defined murine Ph+ ALL cells, we identified Interleukin 7 (IL-7) as the dominant host-factor that attenuates response to BCR-ABL-KIs. To identify potential combination drugs that could overcome this IL-7-dependent BCR-ABL-KI-resistant phenotype, we screened a small molecule library including FDA-approved drugs. Among the validated hits, the well-tolerated anti-malarial drug dihydroartemisinin (DHA) displayed potent activity in vitro and modest in vivo monotherapy activity against engineered murine BCR-ABL-KI–resistant Ph+ ALL. Strikingly, co-treatment with DHA and dasatinib in vivo strongly reduced primary leukemia burden and improved long-term survival in a murine model that faithfully captures the BCR-ABL-KI-resistant phenotype of human Ph+ ALL. This co-treatment protocol durably cured 90% of treated animals, suggesting that this cell-based screening approach efficiently identified drugs that could be rapidly moved to human clinical testing
doi:10.1177/1087057113501081
PMCID: PMC3963394  PMID: 23989453
2.  A Quantitative High Throughput Screen Identifies Novel Inhibitors of the Interaction of Thyroid Receptor β with a Peptide of Steroid Receptor Coactivator 2 
Journal of biomolecular screening  2011;16(6):618-627.
The thyroid hormone receptors (TR) are members of the nuclear hormone receptor (NHR) superfamily that regulate development, growth, and metabolism. Upon ligand binding, TR releases bound corepressors and recruits coactivators to modulate target gene expression. Steroid Receptor Coactivator 2 (SRC2) is an important coregulator that interacts with TRβ to activate gene transcription. To identify novel inhibitors of the TRβ and SRC2 interaction, we performed a quantitative high throughput screen (qHTS) of a TRβ-SRC2 fluorescence polarization assay against more than 290,000 small molecules. The qHTS assayed compounds at six concentrations up to 92 uM to generate titration-response curves and determine the potency and efficacy of all compounds. The qHTS dataset enabled the characterization of actives for structure-activity relationships as well as for potential artifacts such as fluorescence interference. Selected qHTS actives were tested in the screening assay using fluoroprobes labeled with Texas Red or fluorescein. The retest identified 19 series and 4 singletons as active in both assays with 40% or greater efficacy, free of compound interference and not toxic to mammalian cells. Selected compounds were tested as independent samples and a methylsulfonylnitrobenzoate series inhibited the TRβ-SRC2 interaction with 5 uM IC50. This series represents a new class of thyroid hormone receptor-coactivator modulators.
doi:10.1177/1087057111402199
PMCID: PMC3162318  PMID: 21482722
thyroid receptor; small molecule; HTS; coactivator; protein-protein interaction
3.  A High-Throughput Ligand Competition Binding Assay for the Androgen Receptor and other Nuclear Receptors 
Standardized, automated ligand binding assays facilitate evaluation of endocrine activities of environmental chemicals and identification of antagonists of nuclear receptor ligands. Many current assays rely on fluorescently labeled ligands which are significantly different from the native ligands. We describe a radiolabeled ligand competition scintillation proximity assay (SPA) for the androgen receptor (AR) using Ni-coated 384-well FlashPlates® and liganded AR-LBD protein. This highly reproducible, low cost assay is well-suited for automated HTS. Additionally, we show that this assay can be adapted to measure ligand affinities for other nuclear receptors (peroxisome proliferation activated receptor γ, thyroid receptors α and β).
doi:10.1177/1087057108326662
PMCID: PMC2632761  PMID: 19171919
Scintillation Proximity Assay; androgen receptor; high-throughput screening; endocrine disrupting chemicals; nuclear receptors

Results 1-3 (3)